X-ray diffraction
2.5Å resolution

Crystal structure of Lactose synthase complex with UDP


Function and Biology Details

Reactions catalysed:
UDP-alpha-D-galactose + D-glucose = UDP + lactose
UDP-alpha-D-galactose + N-acetyl-beta-D-glucosaminylglycopeptide = UDP + beta-D-galactosyl-(1->4)-N-acetyl-beta-D-glucosaminylglycopeptide
UDP-alpha-D-galactose + N-acetyl-D-glucosamine = UDP + N-acetyllactosamine
Biochemical function:
Cellular component:

Structure analysis Details

Assembly composition:
Non-polymer only dimer (preferred)
Entry contents:
2 distinct polypeptide molecules
Macromolecules (2 distinct):
Alpha-lactalbumin Chains: A, C
Molecule details ›
Chains: A, C
Length: 123 amino acids
Theoretical weight: 14.02 KDa
Source organism: Mus musculus
Expression system: Escherichia coli BL21
  • Canonical: P29752 (Residues: 21-143; Coverage: 100%)
Gene name: Lalba
Sequence domains: C-type lysozyme/alpha-lactalbumin family
Structure domains: Lysozyme
Processed beta-1,4-galactosyltransferase 1 Chains: B, D
Molecule details ›
Chains: B, D
Length: 286 amino acids
Theoretical weight: 33.37 KDa
Source organism: Bos taurus
Expression system: Escherichia coli BL21
  • Canonical: P08037 (Residues: 130-402; Coverage: 68%)
Gene names: B4GALT1, GALT, GGTB2
Sequence domains:
Structure domains: Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A

Ligands and Environments

3 bound ligands:

1 modified residue:

Experiments and Validation Details

Entry percentile scores
X-ray source: NSLS BEAMLINE X9B
Spacegroup: P21
Unit cell:
a: 55.171Å b: 99.013Å c: 102.382Å
α: 90° β: 103.92° γ: 90°
R R work R free
0.197 0.197 0.255
Expression system: Escherichia coli BL21